1. Technical Field
The present invention relates to a vehicle light controller which automatically turns on a vehicle light according to the state of a rainfall.
2. Description of the Related Art
While a driver is driving a vehicle, in the case that it happens to rain, there is a fear that the driving visibility of the driver can be lowered, or a fear that the recognition of the existence of this vehicle from other vehicles or pedestrians can be lowered. Thus, as the countermeasures against such fear, preferably, the light of vehicle may be turned on.
On the other hand, there has been already popularized an automatic light apparatus which can automatically turn on and off the light of a vehicle according to the brightness of the running environment of a vehicle, that is, turns on the vehicle light when actual illumination is lowered than reference illumination since the vehicle enters a tunnel or the like, and turns off the light when the illumination becomes equal to or higher than the reference illumination.
Thus, in order to turn on the vehicle light automatically in the case of a rainfall as well, for example, in JP-A-2005-199974, there is proposed an apparatus which uses the fact that, in the rainfall, even though the illumination is not reduced down to the reference illumination of an ordinary automatic light apparatus, the illumination is lowered than the illumination in the case of non-rainfall, when raindrops are detected by a rain sensor, can switch the value of the reference illumination of the automatic light apparatus over to a higher value.
The disclosed apparatus aims at attaining the following object. That is, in the state of a rainfall in which the running environment becomes darker slightly, a vehicle light such as head lamps, small lamps, or room lamps are automatically turned on to thereby allow the enhancement of the driving visibility of the driver of own vehicle or to allow other vehicles and pedestrians to easily recognize the existence of own vehicle.
Here, according to the above-mentioned conventional apparatus, when, while the vehicle is running in a state where the vehicle light is on according to the rainfall, the vehicle comes into a rain block object such as a tunnel, the rain sensor determines that the rainfall is stopped.
When it is determined that the rainfall has been stopped, the reference illumination of the automatic light apparatus is returned to the normal low value. Thus, since the normal reference illumination is set according to which the light can be turned on within the tunnel, the turn-on state of the light is kept on while the vehicle is running within the tunnel even in the case that the rain sensor does not detect a rainfall.
However, in the case that the rainfall state remains still also in the exit of the tunnel, since the brightness in surround of the vehicle is higher than the normal reference illumination, immediately when the vehicle runs out from the tunnel, the automatic light apparatus turns off the light.
And, in the above-mentioned conventional automatic light apparatus, there is found the following problem: that is, during the time necessary from the time, when the rain sensor newly detects a raindrop, to the time when the apparatus determines that the vehicle environmental state is a rainfall state and thus switches the reference illumination, the driver has to drive the vehicle with the light turned off in a visibility difficult state and in other difficult states.
Further, the automatic light control, within the tunnel exit, must turn off the light which has been on within the tunnel, and next must turn on it again. This repetition of turn on and off of the light bothers the driver, and also can raise a possibility that such on/off repetition can embarrass the drivers of other vehicles running ahead and behind the vehicle wondering if such on/off repetition tells some intention.
Thus, the present invention aims at solving the problems found in the above-mentioned automatic light apparatus. Specifically, it is an object of the invention to provide a vehicle light controller which prevents the light of a vehicle turned on according to a rainfall from being turned off in the exit of a rain block object, thereby being able to maintain the driving visibility and the like at a proper level.